Multi-display and Mixed Resolutions

Now that we’ve wired a single HDMI source in and a single HDMI out, let’s get fancy, shall we.

Many meeting installations are starting to employ multiple displays, and some soft-codec applications

like Microsoft Teams will soon support these scenarios.

So we’ll start by exploring the second output of the decoder. If you visit the Decoder’s properties,

you’ll see an option for HDMI Output Mode.

Let’s go and add another Generic Display to our design, as a destination for this second output.

We’ll just change the property from HDMI 1 to both “HDM1 and 2”, and we’ll wire it up.

You’ll notice in the Decoder’s control panel that this automatically gives you a second section with video

routing options for your second output. It looks identical to your first output options, except it will have

one additional button that says “Follow H1.” In follow mode, the second output’s source will follow any

changes made to the first output’s source. This isn’t a permanent property, but a dynamically selectable

button you can change while the system is live.

Also, don’t forget that in order to achieve dual outputs on the NV Series, all video sources whose

AV stream is wired to this decoder will be limited to 1080p60, which is done through EDID. If your

installation needs 4K, you’ll want to upgrade the system with a second NV-32-H.

In fact, let’s do just that and see what happens. I’ll add another to my inventory and configure it as a

decoder, and assign its AV sources to be the same options I’m getting from my encoder. This means that

we are now multicasting our input sources, because they are available to multiple different output

devices on the network. You can multicast your 4K streams—again, as long as the encoder is only

encoding one stream at a time. But if your second decoder selects a different source, forcing your

encoder to encode two different streams, then it can only encode those streams at 1080p, not 4K.

When this happens, an event occurs that’s known as a Hot Plug Event, which essentially involves all the

handshaking that happens when a source and a display are connected. If your first decoder is displaying

a 4K signal when the second decoder requests a different stream, then both devices will experience a

Hot Plug Event while the encoder “downshifts” from 4K so that it can transmit both streams in 1080. If

you open the Encoder’s control panel, you’ll see a setting called “4k60 – One Hot Plug Event.”

This is generally fine for something like a conference room where you’re selecting your inputs

at the top of the meeting. But if you’re using it in a big, all-hands meeting (with tons of judgy people),

you don’t want to interrupt the video feed when the second decoder requests a stream.

We recommend changing this setting to “1080p60 Max – No Hot Plug Events.” This will limit all

the EDIDS to maximum resolution of 1080p60, regardless of whether the source is 4K. This way all your

content will always be 1080, which will avoid any disruptions when your encoder shifts from streaming a

single source to multiple sources.

Of course, if you really do need multiple 4K sources available at a time, leave this setting on 4k. Then, you simply add

another encoder to your design. Now each source is being encoded in 4K by its own device, so you don’t

experience any of that downshifting that happens when they’re encoded by the same device.

Let’s look at another scenario – don’t forget that you can also enable one HDMI output from an encoder.

If you select an encoder and look at its properties, you’ll see there is an option for HDMI Output

Mode, which by default is set to None. You can set this to HDMI 1 to get a single output from this unit—

note that only HDMI 1 is an option. HDMI2 is not available when the unit is configured as an encoder.

And also keep in mind that the source available for this output will be limited to the local HDMI inputs.

That’s because the NV video endpoint can only operate as an encoder or a decoder, so if this unit

is already working as an encoder, then it cannot decode any of the video streams to deliver to your local HDMI output.

So this option would most commonly be useful as a local courtesy preview, for instance.

Once you wire a display to this HDMI output, you’ll see that you have video routing options within your

encoder control panel, but they’re limited to the graphic options and local HDMI sources – no AV streams.

And while it’s probably obvious at this point, it’s also worth a reminder that if you use any of your local

HDMI inputs when the device is in Decoder mode, those sources are *only* available to that device,

because they are never encoded onto the network to be selectable from another device.

In the next section we’ll look at what happens when you want to process or route the audio

independently of the video. So take a quick break, and come back for the next section.